Hello,
the default behavior with all the WooCommerce shops is to hide the checkout form when the cart is empty. This is valid whether the Multi-Step Checkout plugin is activated or deactivated.
The logic behind is: what should the client check out if there are not products to check out? Or what is the price should the client pay at the checkout?
If the client doesn’t need to pay anything, or doesn’t need to add any product in the cart, then you might look into building in a contact form that collects the billing/shipping address of the client.
Short answer to your question: no, there is no way to show the checkout form if the cart is empty.
